Audio sync issues with speed control, pitch and keyframes
The following seems to work. I’ve included the blend-file.

The movie is ”Spring”  from the Open Movie project of Blender. You can download it here.
Let’s say you want to speed up the movie from time 16+23 (frame 407); just after the falling waterdrop with distinct sound until the dog chasing  after the wood stick (time: 42+23 or frame1031).

Add the movie. The frame rate is 25 f/s.
Add speed Control effect strip
Disable stretch to input Strip Length. Set the speed factor to 1.
Place timeline cursor at position frame 406. Keyframe the speed factor to 1.
Select the sound strip and keyframe the pitch to value 1.
Select the speed Control strip
Move to frame 407. Keyframe the speed factor to 3 (triple the speed)
Select the sound strip and keyframe the pitch to value 3.

So, you create a very abrupt speed up from frame 407 (see the block profile in graph editor in figure 1). Now comes the tricky part. You want to triple the speed until the original time 42+23 or frame 1030. But the actual frame 1030 (after the speed up) is now way further in the timeline. You can see this happening, if you select the actual frame 1030 and disable the speed control (shortcut: H).
So, until which frame or time do we have to speed up? You want to play the original time period of 26 s (42+23 s – 16+23 s) with 3x speed. So, it will only take 26s/3 = 8+16 s. So, the speed control should be reset to one after 8+16 s or at time 25+14s or about  614. The calculation in terms of frames is the same. The original range of 1030 – 407= 623 frames is played at 3x. So, they will take only about 623/3 or about 207  frames  of time. The speed control should be reset at 407 + 207 = 614.

Select the speed Control strip. Move to time 25+14 or frame 614.
Keyframe the speed factor to 1.
Select the sound strip and keyframe the pitch to value 1.

Don’t forget to View &gt; Refresh All (Ctrl+R) to remove the eventual cache. The indicated period will be played at 3x no matter from where you start.